Investigators say they haven’t been able to determine what caused a significant fire at a north side business Sunday morning.

Seventeen fire fighters from three stations responded, at about 3:30am, to the 2600 block of 2nd avenue north.

An addition at the back of the building was fully engulfed in flames and it took about two hours to extinguish.

Two neighbouring buildings were also damaged.

Total damages are estimated at around $400,000.

Due to the extent of damage to the building and materials, fire investigators say they haven’t been able to pin-point the cause.

Anyone who saw the fire or has information about it can call the Fire Prevention Bureau.

On Thursday morning, 23 firefighters from four stations were called to a four-story apartment building along the 300 block of Highlands Boulevard after a 911 caller reported smoke and visible flames coming from a balcony.

Firefighters were able to put out the blaze with minimal damage.

Investigators say the fire was accidental due to the improper disposal of a cigarette.

The homeowner is not a smoker though and officials say it may have originated from another unit.

Lethbridge Fire and Emergency Services is reminding residents to put out smoking materials in a non-combustible container filled with sand or water.